Julian Assange has thumbed his nose at Swedish investigators, who he says have robbed him of his freedom for six years, by releasing the answers he gave to them under questioning in Ecuador’s London embassy last month.

The decision to issue the statement, which contains for the first time a detailed account by the WikiLeaks founder of his encounter with a woman in August 2010 who made rape allegations against him, marks a fresh twist in a case in which Assange claims an early leak of information from the Swedish police has shaped opinion.

The transcript of a police interview with the woman was leaked to media in December 2010, which the Australian, who has not been charged with any crime, says helped to establish an aura of guilt around him.

Since then, Assange has repeatedly asked to be allowed to tell his side of the story to prosecutors, but until recently they insisted he come to Sweden for questioning. Assange has been confined to Ecuador’s cramped London embassy since June 2012, after claiming asylum to avoid extradition over the allegations.

“I am now releasing my statement to the public,” Assange says in a letter accompanying the document. “The reason is simple. I want people to know the truth about how abusive this process has been.”

The release of the statement is likely to be met with dismay in Sweden, where prosecutors’ desire for personal aspects of the case to remain confidential has led them to deny Assange access to evidence against him, because of the risk that it might become public.

The move was condemned by Elisabeth Massi Fritz, the lawyer for Assange’s accuser, who said that his decision to release details of their relationship the statement was “unfortunate”.

She later accused Assange of “violating” her client in the media. “Assange seems to be desperate. As soon as he has something to say he calls the media and is conducting the investigation through the media,” she told Swedish broadcaster SVT.

“The only thing I can say is that Assange has low credibility, which we will prove when we prosecute. I expect the prosecutor to issue charges. I also expect Assange to stop violating my client in the media. She has suffered more than enough for six years.”

In correspondence with Ecuador over the conditions of Assange’s interrogation, the Swedish prosecutor in the case, Marianne Ny, insisted the proceedings remain private to protect the plaintiff. A spokesperson for Ny told the Guardian she was awaiting the formal report on the interviews from Ecuador, due this month, before deciding on her next step.

The statement, which Assange read out to investigators in response to their questioning, contains a sustained attack on the prosecutor, for whom he claims the interview in London was “simply a ruse to tick a box to ensure the technical possibility to indict me”. Under Swedish law, an interview with the suspect is an essential step before issuing charges.

The statement fleshes out Assange’s argument that he is at risk of extradition from Sweden to the US to face espionage charges – and potentially a life behind bars.

Until now, Assange has not described his sexual encounter with his accuser. He has not publicly apologised to her or tried to mitigate the distress she has been caused.

Assange’s statement says that, owing to US hostility towards WikiLeaks, his bank cards were blocked after his arrival in Sweden in the summer of 2010 at the peak of the Pentagon’s conflict with him over the release of a trove of diplomatic and military documents. This made him highly dependent on the hospitality of others.

The woman “appeared to be sympathetic to my plight and also appeared to be romantically interested in me”, Assange told prosecutors. “She was not close to people I was close to, so it seemed that those who meant me harm would be unlikely to try to find me by monitoring her movements.”

She “made it very clear that she wanted to have sexual intercourse” with Assange and placed his hands on her breasts while in a cinema, he continued. “I felt concerned about the intensity of [her] interest and I also deeply loved another woman, which played on my mind and left me emotionally distracted.”

The intensity of her interest made him fear how she might react if she felt he was rejecting her, he said. He claimed he later discovered she had collected dozens of photos of him in the weeks before they met, her Flickr photo account filled with “pages and pages” of photos of Assange.

After they had unprotected sex, she wanted him to have a test for sexually transmitted diseases, the statement continues.

“We were in agreement and arranged to meet the following day in the nearby park around lunchtime, when I would have time to get tested. She said she was fine and seemed at ease. You can imagine my disbelief when I woke the next morning to the news that I had been arrested in my absence for ‘rape’ and that police were ‘hunting’ all over Stockholm for me.”

Assange claims that text messages sent by the woman at the time – access to which his lawyers were allowed only briefly and early in the case – show that she was not asleep during the sex.

“I was certain [she] was not asleep. I was also certain she expressly consented to unprotected sex before such intercourse started.” The woman has insisted that a prerequisite of intercourse was that a condom be used.

He claims the texts also show that the woman said at the time she “did not want to put any charges on Julian Assange”, but that “the police were keen on getting their hands on him” and that she was “shocked when they arrested him” because she “only wanted him to take a test”.

According to the transcripts leaked to the Guardian in 2010, the woman told police she met Assange at a seminar at which he was speaking, and afterwards went to the cinema with him, where they kissed in the back row.

Two days later, she arranged to meet him and they went to her flat. They started to have sex, she said, but she moved away because Assange had not wanted to wear a condom, and he fell asleep. She told police they later had sex at least once when he had “unwillingly” worn a condom, but the following morning, after she had gone to buy breakfast and then climbed back into bed and fallen asleep, she had woken to find him having sex with her without a condom.

According to the statement, she told him: “You better not have HIV” and he answered “Of course not,” but “she couldn’t be bothered to tell him one more time because she had been going on about the condom all night. She had never had unprotected sex before.” The statement says that she bought the morning after pill and took an STD test but when she telephoned Assange asking him to be tested he said he didn’t have the time.

Assange has made no secret of his contempt for the Swedish prosecutor, but his decision to release his side of the story appears calculated to place further pressure on Ny to end the stalemate in the case, either by issuing a rape charge – and implicitly explaining the evidence for the charge – or lifting the arrest warrant against him.

“In the past the prosecution has fed partial information to tabloids that politically oppose me,” Assange said. “It is better that my statement, which I am happy with, and which makes it obvious to all that I am innocent, sees the light in full.”